Urinary incontinence, arising from several conditions, is a common symptom in many women, especially women who had previous vaginal deliveries. Stress urinary incontinence (SUI) is the involuntary loss of urine due to increases in intra-abdominal pressure associated with laughing, lifting, coughing, or other physical activity. SUI may be caused by excessive bladder neck mobility (hypermobility) and/or intrinsic sphincter deficiency (ISD). Bladder neck hypermobility is typically the result of weak periurethral and bladder support tissue which permits the movement of the bladder neck and proximal urethra during times of increased intra-abdominal pressure. ISD is an inherent weakness of the internal urinary sphincter due to scarring or denervation which renders the internal urinary sphincter incompetent. An incompetent urinary sphincter may allow SUI in the absence of bladder neck hypermobility as urine is pushed through the incompetent sphincter with increases in intra-abdominal pressure. Some patients have both bladder neck hypermobility and ISD resulting in extreme SUI. It is important to recognize and understand that SUI is a symptom, not a disease or disorder per se.
A variety of techniques has arisen for treating the symptom of SUI. The techniques primarily involve supporting the urethra in a position where the flow of urine may be controlled by urethral compression during increases in intra-abdominal pressure. FIG. 1 illustrates the problem. Internal parts 10 of a female include a bladder 12 and a urethra 14 leading from the bladder. The urethra is a relatively small tubular organ leading from the bladder to the external portion of the body. FIG. 1 also illustrates the pubic bone 18 and the vagina 16. The urethra is shown in a relatively unsupported position, slumped to the right in FIG. 1, where the urethral sphincter may be unable to control the flow of urine in the patient.
Prior art techniques include a variety of ways to support the urethra. These ways include suturing to musculature or fascia beneath the urethra. Perhaps the most popular recent methods have involved placing a sling or hammock beneath the urethra, and supporting the hammock by anchoring it to fascia or other suitable supports, such as rectus muscle, the pubic bone, Cooper's ligament, or to subcutaneous tissue above the rectus fascia. Prior art slings are depicted in FIGS. 2 and 3. In FIG. 2, a prior art sling 20 includes a central portion 22 and means for attaching 24, 26 on the ends of the sling. These means for attaching may include tabs as shown or may include a suture 28 to allow a surgeon to draw the ends of the sling through the patient. FIG. 3 depicts another prior art sling 30. This sling has a central portion 32 with visual indicators 34 to aid the surgeon in positioning the sling under the urethra. The sling may be tapered towards the ends 36, and also has suture receiving sites 38 to resist tearing as the surgeon extends the sling through the body of the patient. Certain of these materials are disclosed in U.S. Pat. Nos. 6,042,534, and in 5,934,283 and 6,010,447, all incorporated herein by reference in their entirety. These techniques may involve anchoring to the pubic bone and may be objectionable to the patient. Other techniques for implantation with loose tapes are numerous in the prior art, including U.S. Pat. Nos. 5,899,909 and 6,273,852, incorporated herein by reference in their entirety.
These prior art techniques have disadvantages in that they are not necessarily stable within the body of the patient. That is, once the sling is placed under the urethra or within tissues of the pelvic floor, the sling may tend to move, and thus the patient does not receive the benefit of the surgeon's precise placement of the sling for supporting the pelvic floor or the urethra, and gaining the best control over incontinence. Other disadvantages lie in the design of the sling itself. Since at least the central portion of the sling has a constant width, it may be subject to rolling or bunching under the urethra. This may tend to re-form a wide band into a narrow supporting band underneath the urethra, providing less support and possibly cutting into the urethra in extreme cases.
What is needed are improved or alternative slings or hammocks for urethral support. What is needed are slings that will remain where the surgeon places them, and which will gently and reliably support the urethra and potentially other tissue structures, allowing a patient long-term relief from stress urinary incontinence.